Developmental characteristics of temporal sharp transients in the EEG of normal preterm and term newborns

Abstract

-Objective: To describe developmental characteristics, morphological aspects and incidence of temporal sharp transients (TST) in normal preterm and term newborns at matched conceptional ages (CA). Method: Neonatal EEGs from two groups of normal newborns were evaluated in order to identify and characterize TST. Group I (n=40) consisted of newborns from 34 to 40 weeks of gestational age (GA) that were submitted to a single EEG between 24 and 48 hours of life. Group II consisted of 10 preterm newborns with GA between 30-32 weeks, followed with a weekly EEG until they reached term. Morphology of TST was divided in 3 groups (temporal sawtooth, isolated transients or repetitive transients). TST index, density and total number were calculated in each polysomnography and related to sleep stages and CA. Laterality (right/ left) was also evaluated. The groups were compared at 34, 36, 38 and 40 weeks of CA. Results: TST index and density decreased with the increase of CA in both groups (p<0.0001). The temporal sawtooth feature was registered in both groups only at 34 weeks. Although rare, repetitive and isolated TST were the most prevalent morphology between 36 -40 weeks CA. Significant intragroup difference was observed in the comparison of TST density in REM and transitional sleep in GI. Moreover, isolated TST morphology was significant higher in GI at 34 weeks when compared to the others CA. No intragroup differences were observed on GII. No significant differences between the groups were observed considering TST number, index, density, morphology or laterality, at the matched CA. Conclusion: TST are normal features of neonatal EEG, as they are registered in normal newborns. Its incidence varies accordingly to morphology and they tend to disappear following the increase of CA. Temporal sawtooth appears more often in preterm newborns. Our results suggest that TST index, density and morphology variability may be a function of CA.KEY WORDS: neonatal EEG, temporal sharp waves, preterm newborn, sleep ontogenesis. Características das ondas agudas temporais no EEG de recém-nascidos normais pré-termo e a termoRESUMO -Objetivo: Descrever as características, aspectos morfológicos e incidência das ondas agudas temporais (OAT) em recém -nascido pré-termo e a termo pareados por idade concepcional (IC). Método: OAT foram identificadas e analisadas nos EEGs de dois grupos de recém -nascidos normais. O GI (n=40) foi constituído de recém -nascidos com idade gestacional (IG) de 34 a 40 semanas, submetidos a EEG com 24-48 horas de vida. O GII consistia de 10 recém -nascidos pré -termo com IG entre 30 -32 semanas, seguidos com EEG semanal até atingirem IC de 42 semanas. As OAT foram divididas de acordo com sua morfologia em serrilhada, isolada e repetitivas. O número total, índice e densidade de OAT foram calculados em cada EEG neonatal e relacionados ao estágio do sono e IC. A lateralidade (esquerda/direita) também foi analisada. Os grupos foram comparados nas seguintes semanas de IC: 34, 36,38 e 40 semanas. Resultados: O índice ...

Electroencephalogram in premature infants: from normal to pathological activity

“…• изолированные -единичные моно-или дифазные волны амплитудой 50-250 мкВ; • повторяющиеся -вспышки 2 и более острых или «гребенчатых» ритмичных волн, разделенных интервалами до 2 с, амплитудой <100 мкВ; • «пилообразный» паттерн -острые волны частотой 4-7 Гц и амплитудой 150-250 мкВ, сгруппированные в короткие (4-6, длительностью <2 c) ритмичные вспышки (синоним: височные тета-вспышки, или PTΘ) [9,29,39]. Изолированным и повторяющимся височным волнам приписывают возможность более длительной персистенции, в норме -вплоть до 40 нед ПКВ [29].…”

Analysis of frontal sharp transients in 32 neonatal polysomnography in healthy fullterm newborns

“…The EEG can be used as a diagnostic tool for the investigation of neonatal seizures, and may help in establishing prognosis in certain neonatal conditions. Many studies have addressed the graphic elements of EEG re c o rdings in newborns (NB), and their behavior during sleep, to establish the boundaries between normal and pathological findings 6,[10][11][12][13][14][15][16][17] .…”